[22q11.2 deletion syndrome diagnosed in an adult male]

Robert-Jan Hassing1, Judith M A Verhagen, Ingrid M B H van de Laar

  • 1Erasmus Medisch Centrum, Afd. Interne Geneeskunde, Rotterdam, the Netherlands. r.hassing@erasmusmc.nl

Abstract

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Overview
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The Y Chromosome Determines Maleness

The Y chromosome is a sex chromosome found in several vertebrates and mammals, including humans. In addition to 22 pairs of autosomes, the human males have one X chromosome and one Y chromosome. In these organisms, the presence or absence of the Y chromosome determines the development of male traits.
Evolution
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Diploid organisms inherit genetic material through chromosomes from both parents. Copies of the same gene are known as alleles. In most cases, both alleles are simultaneously expressed and allow various cellular processes to function optimally. If one of the alleles is missing or mutated, the expression of the other allele can compensate; however, this is not true for all genes.
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